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Imine-linked covalent organic frameworks (COFs) have been widely studied in the field of photocatalytic hydrogen production due to their easy synthesis, good crystallinity, tunable pore size and excellent thermal and chemical stability. However, the effect of substituent type on the photocatalytic properties of COFs has been rarely studied. Herein, six COFs with COF-TpPa as the basic skeleton were synthesized by introducing different types of substituents in the p-phenylenediamine benzene ring, among which TpPa-CN2 was prepared for the first time. The COFs showed similar structures but great differences in their photoelectric properties. TpPa-Cl2 and TpPa-CN2 demonstrated a superior hydrogen evolution performance compared to the other four COFs when ascorbic acid was used as the electron sacrificial agent and Pt as the cocatalyst. The photocatalytic hydrogen evolution (PHE) rate of TpPa-Cl2 and TpPa-CN2 was as high as 99.23 and 76.93 mmol g−1 h−1, respectively. The introduction of chlorine and cyanide improved the visible-light response, hydrophilicity and photo-carrier separation ability of TpPa COF, which contributed to the enhanced PHE efficiency of TpPa-Cl2 and TpPa-CN2. This study provides a strong basis for the systematic fine-tuning of the structural and physico-chemical properties of COFs aiming to achieve COF materials with ultra-high photocatalytic activity. [ABSTRACT FROM AUTHOR]

Synergetic effects in Au–Ag bimetallic nanoclusters (BNCs) more favorably enhanced electrochemical redox induced electrochemiluminescence (ECL) over photoexcitation induced photoluminescence (PL); this not only led to Au–Ag BNCs with enhanced bandgap-engineered ECL compared to Au NCs, but it also generated surface-defect related ECL to enhance the total ECL intensity. [ABSTRACT FROM AUTHOR]

Correction for 'Mechanistic investigations into synergistically enhanced radiative-charge-transfer in Au–Ag bimetallic nanoclusters' by Jianbo Liu et al., Chem. Commun., 2020, 56, 5665–5668, DOI: 10.1039/D0CC02047H. [ABSTRACT FROM AUTHOR]

This study aimed to promote the separation of photogenerated carriers and improve the redox performance of graphite carbon nitride (g-C 3 N 4 ) by synthesizing a double-heterojunction-structure photocatalyst, g-C 3 N 4 /(101)-(001)-TiO 2 , through the solvothermal method. The photocatalyst comprised a Z-system formed from g-C 3 N 4 and the (101) plane of TiO 2 , as well as a surface heterojunction formed from the (101) and (001) planes of TiO 2 . The results showed that g-C 3 N 4 /(101)-(001)-TiO 2 had strong photocatalytic activity and stable performance in the photodegradation of paracetamol. The active species ·O 2 - and ·OH were found to play important roles in the photocatalytic degradation of paracetamol through a radical-quenching experiment. The charge-transfer mechanism was also described in detail. Overall, this work provided a new strategy for the Z-system heterojunction and opened up the application of this structure in the degradation of organic pollutants., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)